This invention relates to an intake system for a multi-intake valve type engine, and more particularly to an induction system that permits high performance without sacrificing low speed running characteristics or good transitional running.
It is known that the maximum power output of an engine can be improved by providing multiple intake valves each served by a respective intake passage. Such an arrangement improves the breathing ability and, accordingly, permits significant power improvements over single valve engines. However, such arrangements are normally used only in high performance automotives wherein smooth running at low speeds and low and medium speed torques are not particularly important. Normally such high output engines do not run well at low speeds because the velocity of air flow at such low speeds is insufficient to insure the delivery of a uniform charge to the chambers and efficient combustion in the chambers.
It has been proposed to improve the running characteristics of such engines at low speeds by providing a control valve in the intake passage with one of the intake valves so that flow through this passage is either restricted or completely obstructed at low speeds. Such an arrangement has the effect of increasing the velocity of the charge delivered to the chambers due to an effective restriction in the intake passage area. The increased velocity improves running characteristics. However, such arrangements, as have been previously proposed, provide relatively poor transitional running.
It is, therefore, a principal object of this invention to provide an improved induction system for an internal combustion engine.
It is another object of the invention to provide an engine induction system in which maximum performance is achieved without sacrificing good running at low and transitional conditions.
As has been noted, it has been proposed to provide a control valve for controlling the flow through one of the engine induction passages to improve low speed performance. Previously this has been done by virtue of aa mechanical linkage system that delays opening of the control valve until a predetermined of the main throttle valve has occurred. However, such an arrangement is not fully indicative of the actual running conditions and may not provide the degree of induction system control necessary to achieve the aforenoted purposes.
It is, therefore, a still further object of this invention to provide an improved throttle control arrangement for a multiple intake passage type of internal combustion engine induction system.
In engines embodying multiple intake passages for each chamber, it is also desirable to insure good fuel distribution to the chamber through the respective intake passages. If a fuel injection system is used, this problem becomes particularly acute.
It is, therefore, a still further object of this invention to provide in an improved multiple intake passage induction system for an engine an improved fuel injection arrangement.
In engines of the type described above and in certain other types of engines, it may be desirable to provide a throttle valve in an intake passage that is controlled in response to engine load. In accordance with another feature of this invention, it is an object to provide an improved control arrangement for such a throttle valve.